Refrigeration unit for internalcombustion engines



H. G. SCHWARZ Sept. 18, 1945.

REFRIGERATION UNIT FOR INTERNAL-COMBUSTION ENGINES Filed Sept. 20, 19415 Sheets-Sheet l Q INVENTOR HENRY G. Sam 2 BY ATTO EYS Sept. 18, 1945.H. e. SCHWARZ REFRIGERATION UNIT FOR INTERNAL-COMBUSTION ENGINES FiledSept. 20, 1941 5 Sheets-Sheet 2 5 R Y m2 m N R E O Sept. 18, 1945. H. a.scHwARz REFRIGERATION 'UNIT FOR INTERNAL-COMBUSTION ENGINES F iled Sept.20, 1941 5 Sheets-Sheet 3 INVENTOR G. 5c 2,

BY HENR ATTO EYSU Sept. 18, 1945. H. G. scHwARz REFRIGERATION UNIT FORINTERNAL-COMBUSTION ENGINES Filed Sept. 20, 1941 5 Sheets-Sheet 4 INVENTOR HENRY G.SCHWARZ BY a ATTOR Y6 Patented Sept. ,18, 1945 UNITED 7STATES PATENT OFFICE REFRIGERATION UNIT FOR INTERNAL- COMBUSTION ENGINES2 Claims.

This invention relates to an improvement in. refrigeration units forinternal combustion engines, more particularly aircraft engines.

As is known, there is a need for positive, controlled cooling byrefrigeration of high speed internal combustion engines, particularlyaircraft engines. Such cooling means must be highly emcient, light inweight, and capable Of close control. In my application Ser. No.334,326, filed May 10, 1940, now Patent Number 2,261,418, I havedisclosed a satisfactory refrigeration unit for internal combustionengines of an aircraft, specifically comprising an oil cooler. This unitincludes a compressor driven from the aircraft engine, and hence itsoperation places a small but appreciable load upon the aircraft engine.The inclusion of moving parts in this refrigeration unit moreovernecessitates inspection and maintenance, and increases the hazards ofmechanical failure.

Now in accordance with the present invention I provide a highly emcientand closely controllable refrigeration unit for use with internalcombustion engines, more particularly aircraft engines, which containsno moving parts (aside from the control mechanism thereof) and which isoperated by the heat energy of the waste exhaust gases of the engine.The refrigeration unit in accordance with my invention may be variouslyused in association with the internal combustion engine on which it isinstalled, thus it may be used to cool the cooling liquid circulatedthrough the jacket of a liquid cooled engine; to cool the engine oil toprevent undue decomposition thereof; or even to cool directly certainportions of the engine, although this last procedure is not ordinarilypracticable in engines designed to operate at high temperatures.

The refrigeration unit in accordance with this invention will ordinarilycomprise an absorbergenerator unit in which the dry refrigerant, asammonia, sulfur dioxide, etc., may be stored and from which it may bedriven off; a condenser, preferably air-cooled; a refrigerating or heattransfer unit proper, in which the liquid to be cooled may be circulatedin heat transfer relationship with the refrigerant; means for supplyinghot exhaust gases of the engine to the absorber-generator unit whenrequired, to drive off the refrigerant therefrom; and automatic controlmechanism responsive to conditions within the refrigerant system, as thepressure of the refrigerant, for controlling the supply of exhaust gasesto the absorber-generator unit.

Further details of my invention will be apparent from the followingdescription of a preferred embodiment thereof, comprising an oil coolerfor aircraft engines, read in conjunction with the accompanyingdrawings, in which:

Fig. 1 is a plan view, partly diagrammatic, showing the installation ofan oil cooler in accordance with my invention in an internal combustionengine of an aircraft.

Fig. 2 is a vertical section through the absorbergenerator unit andcondenser of the oil cooler.

Fig. 3 is an end view of the absorber-generator unit and condenser shownin Fig. 2.

Fig. 4 is a side view, partly in section, of the refrigerating unit ofthe oil cooler.

Fig. 5 is an end view, partly in section, of the refrigerating unit ofFig. 4.

Fig. 6 is a detail plan view, partly in section, of the automatic valvecontrolling the passage of exhaust gases, and its operating mechanism.

Fig. 7 is a horizontal section through the valve mechanism shown in Fig.6.

Fig. 8 is a vertical section through the control mechanism for theautomatic valve.

Fig. 9 is a section on the line 9-9 of Fig. 8.

Fig. 10 is a detail view showing a part of the gear train shown in Fig.8.

Fig. 11 is another detail view showing a further part of the gear trainshown in Fig. 8.

Fig. 12 is a section taken on the line I 2--l 2 of Fig. 11.

Fig. 13 is a detail view of the mechanism shown in Fig. 8, showing theparts in a difierent position.

The improved oil cooler in accordance with my invention comprises, asshown in Fig. 1, an absorber-generator unit A, a condenser B, arefrigerating unit C, an automatic valve D for controlling the exhaustgases, and a control mechanism E for the said valve. The generalinterrelationship and the connections among these several elements areshown in Fig. 1. For clarity, the several elements may be individuallydescribed a follows:

The absorber-generator unit,

The absorber-generator unit, designated in Fig. 1 as A, and shown indetail in Figs. 2 and 3, is formed with an outer wall ll, an inner wallI3, and an intermediate wall, or partition, l5, which, with the endmembers I1, is respectively, form two generally annular chambers 2| and23. The inner of these chambers 2| is filledwith an adsorbent forammonia gas. Preferably the adsorbent will be a solid adsorbent, such assilver nitrate, silica gel, silver chloride, etc. The outer chamber 23is designed to contain a low boiling stable liquid,

such as, for example, CFCla. Through the lower part of the outer chamber2!, which is enlarged to receive it. there passes a conduit 25communicating, through the automatic valve D, with the exhaust manifold3 of the internal combustion engine I.

The condenser The condenser, designated as B in Fig. 1, and

"shown in detail in Figs. 2 and 3. comprises two chambers 21, 29,respectively, in communication with one another through passages 28 andII, controlled by needle valve 33. The chamber-.21 is connected with theupper part oi chamber 23 of the absorber-generator unit by means of 9.ntting 35, while the chamber 29 is connected through passage 31,-controlled by check valve 39, and conduit 4| with the lower part ofchamher 23.

Secured within the chamber 29 is a U-shaped tube 43 through which thecondensing medium, in this case cold air from the exterior of theaircraft, is passed. Tube 43 is connected at its upper end throughconduit 45 with the carbureter air scoop 5 of the internal combustionengine l, and at its lower and through conduit 4'5 with the exterior o!the plane. At the point of connection of th conduit 45 with thecarbureter air scoop 5, close to the intake manifold, a partial vacuumis maintained, and consequently air is continuously drawn throughconduit 61 into the condenser tube 53 and thence through conduit 55 tothe carburetor air scoop. A helical coil 49 surrounds the condenser tube453 within the chamber 29 and is connected at one end through theconduit til with-chamber 28 of the absorber generator unit, and at itsother end through conduit 53 with the automatic control mechanism E.

Positioned within the chamber El is a bellows diaphragm 5d and a plunger55. Plunger E55 carries, at its lower end, a transverse pin El, which,upon being raised suihciently, will lift lever 63 against the spring 68and so lift needle valve 33 from its seat. At its upper end the plungerR55 is connected, at 59, to one end of the drive wire of a flexiblecable 6! of conventional design which leads to the control mechanism E.

The refrigerating unit The refrigerating unit, designated in Fig. l asits seat by a spring "within the diaphragm BI, the tension on whichspring may be adjusted by rotation of shaft 98, to which is connectedone end of the drive wire of a flexible control shaft Ill leading to amanual control 98, which may be conveniently placed in the cockpit oithe plane. The manual control 88' may be similar to that described in myapplication 8.1%. 334,326.

The automatic valve The automatic valve for control or exhaust gases ofthe internal combustion engine, designated as D in Fig. 1, is shown indetail in Figs. 6 and 7. The exhaust manifold 3 from internal combustionengine I leads into a valve chamber in which there is positioned a flapvalve ml, which in one position (that shown in the dotted lines) closesconduit I03 and directs the hot can haust gases from conduit 3 upwardthrough conduit to the absorber-generator unit A, and thence to theatmosphere; while in its other position (that shown in the dot and dashlines) it closes communication between conduits 3 and 25 and directs theexhaust gases from conduit 3 through conduit I03 directly to theatmosphere.

Flap valve IN is operated, through lever I86 and link I01, by lever I09,which forms an armature for a pair of opposed electromagnets I l I andH3.

The control mechanism The automatic control. mechanism controlling theoperation of the valve D is designated as E in Fig. 1, and is shown inFigs. 8 to 13, inclusive. As shown in Fig. 8, the control mechanismincludes a chamber I It in communication, through conduit M, withchamber 83 of the refrigerating unit C, and through passage H1 andconduit 53 .1 with the condenser B.- A needle valve H9 carby means ofconduit ll, to the oil reservoir l or the engine.

The chamber as contains a plurality of U- shaped tubes l3 designed tocontain liquid refrigerant, in this case ammonia, and vertical bafllesit. By means of the bailles the hot oil is forced to flow up and downaround the tubes l3, and the heat carried by the oil is given up to theammonia, whlch'is thereby vaporized.

All the tubes it are open at their upper ends to chamber ll, which is inturn connected. through lateral ports l9, ill, with chamber 83. Ammoniaenters and leaves chamber as through passage 85, communicating withconduit 8?, and thence, through the control mechanism and conduit 53,with condenser E. Passage 85 is controlled by needle valve to connectedwith a bellaws diaphragm cl. Needle valve he is urged to ried by plungeriii of bellows diaphragm I23 controls passageway ill. The plunger i2! isconnected at its lower end, by means of link I25, with lever 821. Thelever 32'! is in turn connected by means of link @29 and bell crank IBIwith rack 033, which is supported upon the roller bearing I85, andmeshes with pinion I31 on shaft 538. Shaft H38 drives, through pinionsI39 and Mi, which are in mesh, the cam shaft i443, which drives, throughthe ratchet clutch I45, cam l ll. Reverse movement of cam M! isprevented by means of ratchet I49 and pawl IN. The gearing is such thatan operative stroke of rack 933' will result in one-half revolution ofcam Ml.

Riding upon-the cam I41 is cam follower i553, which is pivotallysecuredin the control box at 8%. Cam follower 553 carries an L-shaped slotit'll, in which rides a roller H58 carried on the lower end of hellcrank I59, the upper end of which is connected at I69 to the drive wireof flexible cable bi. Also secured to cam follower 853 is a contact railISI adapted, during a portion of the cycle to be described, to be incontact with spring contact member use carried by lever H59. A secondcontact member I55 is also mounted 2,386,033 ber I61. Binding post I15is grounded by being connected to the cam follower I53.

Binding post I1I is connected with electromagnet III of the valvemechanism D, while binding post I12 is connected with electromagnet II3,each of the other leads of the electromagnets being grounded. Bindingpost I13 is connected through a switch 99, which may be convenientlymounted in the cockpit, and a fuse I09, with one side of a 12-boltbattery or other suitable source of electricity, the other side of whichis grounded.

Operation Assume that the elements of the control mechanism have justassumed the position shown in Fig. 8, at which time the adsorbentmaterial in the absorber-generator A will be fully charged with ammonia.If the switch 99 is turned on, current will then pass to binding postI13 through shoe I53 to rail I6I to binding post ill to theelectromagnet I II to ground. Armature I99 will thereupon be lifted toits upper position, thrusting lever I95 upwardly and thereby movingvalve IIJI to its lower position, shown in the dotted lines in Fig. 6.

Hot exhaust gases from the exhaust manifold 9 of the engine will thuspass through conduit 25 to the absorber-generator A, and in passingthrough conduit 25 will give up their heat content to the low boilingliquid contained in chamber 23 surrounding conduit 25. This liquid willthereby be vaporized and pass through fitting 35 into chamber 21 of thecondenser C. In so doing, it will heat uniformly chamber 2i containingthe adsorbed ammonia, which will thereby be driven oil from theadsorbent through conduit 5i and condenser coil 99 to conduit 53. Thereduction in temperature occasioned by passing through condenser coil59, will be suflicient, at the pressure prevailing in this, the highpressure side of the system, to liquefy the greater portion of theammonia.

The ammonia passing through conduit 53 from the condenser will reachcontrol mechanism E, and, exerting pressure through passage II1 upon theneedle valve I I9 on the high pressure side of the system, which valveonly lightly held to its seat, will open this valve when the pressurehas been raised to a predetermined point and pass into chamber I I5 andthence through conduit 81 to passage 85 of the refrigerating unit.Passage 95 is controlled by needle valve 89, which is held against itsseat by a pressure in part dependent upon the manually adjustabletension of spring 99. At a point dependent upon the pressure conditionswithin the chamber 83 and the tension upon the spring 93, needle valve99 will open and ammonia will be permitted to expand from the conduit 81into chamber 83. Liquid ammonia within the chamber 93 will pass throughthe lower ports 19 into the distributing chamber 11, and thence into thetubes 13 within the heat exchange chamber 64. A supply of liquid ammoniawithin the tubes 13 will thus be provided to cool the hot oil passingthrough the chamber 64.

As the pressure in the chamber II5 continues to rise due to thecontinued heating of the adsorbent material in the absorber, the bellowsdiaphragm I23 will tend to be compressed, and plunger HI and lever I21will thereby tend to be moved downwardly against the tension of springI28. Any downward movement of lever I21 is communicated, through linkI29 and bell crank I3I, to the rack I33, and through that and gears I31,I39, I and clutch I45, to the cam I41. long, however, as the roller I58on bell crank I59 is in the upper portion of the L-shaped slot I51 incam follower I53, the cam follower, which, in the position shown in Fig.8, rests upon the low part of the cam, cannot be raised. Hence the camI41 cannot rotate and lever I21 cannot be moved downwardly by thepressure exerted upon it through the bellows diaphragm I23.

However, at the same time that the pressure is rising within chamber II5due to an increase of pressure in the ammonia system, pressure islikewise rising in chamber 21 of the condenser E due to the vaporizationof the volatile fluid contained in chamber 23. This increasein pressurewithin the chamber 21 compresses the bellows diaphragm 54 and lifts theplunger 55, thereby exerting a thrust through the drive wire of theflexible cable BI upon the upper end I69 of the bell crank I59. Thisthrust tends to rock the bell crank I59 about its pivot and to move theroller I59 downwardly within the slot I51. The result is that when boththe pressure within the chamber I I5 and the pressure within the chamber21 has risen to predetermined values, the roller I58 will be brought tothe bottom of the L-shaped slot I51, and the cam follower I53 will beraised by action of the cam as it is rotated one-half turn throughmovement of the lever I21, so that the roller I58 will enter the L ofthe slot.v

It is to be emphasized that before this result can be effected, thepressure in both the chambers concerned, 1. e., chambers I I5 and I21,must have risen to the desired values.

When the cam follower I53 and the bell crank I59 have assumed theposition just described, as shown in Fig. 13, contact between shoe I53and rail I5I will be broken, and contact between members I55 and I61will be closed. Current will then cease to flow through theelectromagnet III, and will flow, instead, through the electromagnet II3. The position of armature I09 and flap valve I9I will thereby bereversed, and the exhaust gases will be cut oif from conduit 25 andcaused to pass directly to the atmosphere through conduit I03.

The liquid ammonia contained in the tube 13 in the refrigerating unit Cwill now be largely va porized by heat absorbed from the hot oil, andthe ammonia vapor present in chamber 11 will be forced through ports 8Iinto the chamber 83, where, when a pressure corresponding to the tensionon spring 93 is reached, it will compress the bellows diaphragm 9i, openthe needle valve 89, and escape through passage and conduit 81 back tothe chamber I I 5.

As soon as heat was shut off from the absorbergenerator unit by movementof flap valve IDI, the pressure within chamber I I5 fell rapidly, andlever I21 was returned to its upper position by the action of springI28. This upward movement of lever I21 resulted in a rearward movementof the rack I33, which motion, however, was not transmitted to the camI41 because of the pres ence of the ratchet clutch I45 and the ratchetI49 and detent I5I, closing valve II9 to shut 011 communication betweenthe high and low pressure sides of the system. Accordingly, when thepressure again rises in chamber II5, as the ammonia flows back from therefrigerator unit through conduit 81, the plunger I2I is again forceddownwardly, and with it the lever I21. In the manner already described,shaft I43 is thereby rotated, and with it the cam I41 is given anotherone-half rotation in a forward direction. This permits cam follower I53to drop oil the high part of the cam.

Prior to this, the transverse pin 51 carried lip-- on the plunger 55within the chamber 21 will have been lifted sumciently far to raise thelever 63 against the tension of spring 64 and lift needle valve 33,thereby opening communication between chambers 21 and 29. The vaporcontained in chamber 21 will accordingly pass to chamber 29, where itwill be condensed by contact with condenser tube 43, and the condensedliquid will flow through passage 81 past the check valve 39, and throughconduit ll back into the now cool chamber 23.

The pressure exerted through the flexible cable 6| upon the bell crank58 is released" as soon as the valve 33 is opened, and the bell crank isthus free to return, under the influence of spring 888, to the positionshown in Fig. 8.

Meanwhile, the ammonia gas has passed from chamber H through passagewayill to conduit 53, and thence through condenser coil 49 and conduit 5ito the now cold adsorbent in chamber 2!, in which it is absorbed. Therelease of pressure within the chamber H5 permits the lever 521, rack H3and associated elements, to return to the position shown in Fig. 8, thisreturn being accomplished, as previously explained, without any mo-=tion of the cam N1.

When cam follower I53 dropped and the cell crank its resumed its upperposition, contact between members N5 and I81 was broken, and contact wasagain closed between the shoe 563 and rail lei. The position of thevalve ml was thus again reversed, and exhaust gases passed through aconduit 25 to'the absorber, thus beginning a new cycle.

It will thus be seen. that the complete cycle comprises two parts in thefirst of which ammonia is driven from the absorber-generator by theail-=- plication of heat thereto, and, alter peming through thecondenser, is permitted to expand through an expansion valve into therefrigerating unit; while in the second the ammonia gas leaving therefrigerating unit is allowed to pass to the now cold absorber-generatorto be there adsorbed. The shift from one part of the cycle to the otheris automatically effected in response to conditions within the system bythe control mechanism 7s; already described.

Control of the amount of cooling and hence of the oil temperature may beeffected by manual adjustment of control as, rotation of which will,through the fiexible' cable or, rotate shaft 95 to increase or decreasethe tension on spring 533 which governs the action of the expansionvalve While my invention has been described in detail as embodied in anoil cooler, it will be appreciated that it may be used on an internalcombustion engine for other purposes, as cooling the cooling liquidtherefor, without essential alteration; and that accordingly myinvention is not limited to an oil cooler or to the particularconstructional details of the preferred embodiment described above. eWhat I claim-and desire to-protect by Letters Patent is:

1. A refrigeration system for use in association with an internalcombustion engine comprising,

in combination, a heat interchanger adapted to receive a liquefiedrefrigerating medium, an absorber containing an adsorbent for therefrigerating medium, a condenser interposed between said heatinterchanger and said absonber, the interchanger, condenser and absorberforming a closed system containing the refrigerating medium, means forsupplying hot exhaust gases of the internal combustion engine to theabsorber to heat the same, and means responsive to variations in thecondition of the refrigerating medium within said system for controllingthe supply of exhaust gases to said absorber, said condenser alsoincluding an air inlet and an air outlet, the latter connected to thecarburetor air supply ofsaid engine, whereby air is drawn through saidcondenser in heat exchange relationship with the refrigerating medium.

2. An oil cooler for an internal combustion engine comprising, incombination, a, heat interchanger adapted to receive a liquefiedrefrigerating medium, means for circulating hot engine oil through saidheat interchanger in heat exchange relationship with said liquefiedrefrigerating medium, an absorber containing an adsorbent for therefrigerating medium, a condenser interposed between said heatinterchanger and said absorber, the interchanger, condenser and absorberforming a closed system containing the refrigerating medium, means forsupplying hot exhaust gases of the internal combustion engine to theabsorber to heat the same, and means responsive to variations in thecondition of the refrigerating medium within said system for controllingthe supply of exhaust gases to said absorber, said condenser alsoincluding an air inlet and an air outlet, the letter connected to thecarbureter air supply of said engine, whereby air'is drawn through saidcondenser in heat exchange relationship with the referigerating medium.

MNRY G. SCHWARZ.

